Cosmic Distance Ladder

Explore 19.4 The H–R Diagram and Cosmic Distances to understand how the Hertzsprung-Russell (H–R) diagram is utilized in determining cosmic distances by establishing luminosity classes and temperatures of stars.
Another way that astronomers can use H-R Diagrams to measure distances is through Star Cluster Main Sequence Fitting. Check out the video and, if you like, you can play with the simulation for yourself.
One of the top rungs in our distance ladder is Supernova Lightcurve Fitting, which allows us to accurately measure the distance to galaxies in the farthest reaches of the universe. If you’d like to play with the simulation from the video, you can find it here.
Finally, watch this excellent summary of The Cosmic Distance Ladder from SciShow.